Transition Metals - Exam Question Walkthrough｜A Level Chemistry (AQA)

[@easymodeexams33]

*I have just noticed a mistake I made in this question!! The charge on the final complex should be a 4- charge since it's a Co2+ and 3 x 2- ethanedioate ligands.

[@marshalkent4735]

keep going with these videos man! so bloody helpful

[@chu2000]

do we not need to put two lone pairs on cis platin and trans platin

[@FrozenPrimordial]

5:40 I thought if you add chlorine to hexaaquacobalt(II) it would form (CoCl4)^2- , is this with dilute HCl? Does this same mechanism also apply to hexaaquairon(II) and hexaaquacopper(II) ?

[@easymodeexams33]

I think you're getting a little bit confused here between ligand substitution reactions and cis-trans isomers that can form. You are perfectly correct though, if you get complete ligand substitution by adding a soluble chlorine-containing reagent you would get [CoCl4]^2- (I'm not sure if you realised but make sure to use square brackets for the charged complexes). I wouldn't really refer to this as a mechanism, just an isomer that can exist due to it being an octahedral complex with 4 of the same monodentate ligand and 2 different monodentate ligands bonded. I hope that clears things up. In this example, I used Cl- ions but it could equally be NH3 or OH- ions also.

[@superrnovaaa]

thank you so much

[@easymodeexams33]

no worries :) good luck

[@cerises9386]

how come linear isn’t a complex shape? like in tollen’s reagent?